The Keratinocyte Core Lab (KCCL) will provide collaboration, service, and training to the investigators participating in the projects of Interdisciplinary Basic Research in Dermatology. The long-term objective of the KCCL is to serve as a resource of information, skills and service in in vitro keratinoctye biology for the members of the Program Project Grant. Specific Aims: 1. Culture normal and pathologic keratinocytes from a number of sources, including newborn foreskin, immortalized cell lines, and skin biopsies. 2. Perform experiments with cultured cells. 3. Maintain special media and provide special techniques for in vitro studies of epidermal metabolism and differentiation. 4. Provide access to and instruction in the use of well-maintained tissue culture facilities and supplies. 5. Train investigators and fellows in the laboratories of principal investigators who wish to learn keratinocyte culture techniques. 6. Develop and adapt new tissue culture techniques to in vitro keratinocyte biology. 7. Maintain the Pathologic Keratinocyte Cell Bank. The KCCL is a shared resource staffed by an investigator and technician with special expertise in in vitro keratinocyte biology, responsible to the investigators of Interdisciplinary Basic Research in Dermatology.